The implementation of a block move engine (BME) (a bit blitter or blitting engine) for rapidly copying blocks of graphics data from one location in memory to another is generally used for graphics processing. BMEs may be extended to include two or more input data streams of identical size which are combined by a logical composition operation and written back to memory as a single data block. The demand for improvements in graphics speed and resolution and the convergence of video and graphics applications onto common platforms has made it is desirable to incorporate a wider selection of functions within the general structure of a BME.